Jamal Abrini

Effects of NaCl and mannitol induced stress on sugarcane (Saccharum sp.) callus cultures

The effects of NaCl and mannitol iso-osmotic stresses on calli issued from sugarcane cultivars (cvs.) R570, CP59-73 and NCo310 were investigated in relation to callus growth, water content, ion and proline concentrations. Callus growth and water content decreased under both stresses with the highest reduction under mannitol-induced osmotic stress. The ion concentration was drastically affected after exposure to NaCl and mannitol. Salt stress induced an increase in Na+ and Cl− accumulation and a decrease in K+ and Ca2+ concentrations. Under mannitol-induced osmotic stress, K+ and Ca2+ concentrations decreased significantly while Na+ and Cl− concentrations remained unchanged. Free proline accumulation occurred under both stresses and was more marked in stress-sensitive cv. than in stress-resistant one. Our results indicated that the physiological mechanisms operating at the plant cell level in response to salt- and osmotic-induced stress in sugarcane cvs. are different. Among the cvs., we concluded that the stress resistance is closely related to the maintain of an adequate water status and a high level of K+ and Ca2+ under both stresses and a low level of Na+ concentration in the presence of NaCl. Thus, sugarcane (Saccharum sp.) can be regarded as a Na+ excluder. We also provided evidence that proline accumulation is a stress-sensitive trait rather than a stress resistance marker.

Antioxidant activity and chemical content of methanol and ethanol extracts from leaves of rockrose (Cistus ladaniferus).

Plants have been used for years as a source of traditional medicine to treat various diseases and conditions. Many of these medicinal plants are also excellent sources for phytochemicals, many of which have potent antioxidant activities [1, 2]. Cistus ladaniferus L., a Cistaceae named rockrose and the most important Cistus species in the perfumery field, is an odorous shrub that grows wild in Portugal, Spain, France (the Esterel massif), Italy (Sicily), and northern regions of Algeria and Morocco [3, 4]. This plant is widely used in herbal medicine and it is claimed to possess various physiological effects. Among the bioactive compounds present in plants, polyphenols and particularly flavonoids are widely appreciated for their potential beneficial health effects, like antioxidant, antimicrobial and anticarcinogenic activities [4]. Pharmacological studies on Cistus extracts reported that they have antibacterial, antifungal, anti-inflammatory [5], antiulcer [6], antiaggregant of platelets [7], hypotensive and spasmolytic activities [8]. It is also commonly used as an antigastric agent by the local population of the North Morocco. This specie is a strongly aromatic plant because of the high essential oil content in their leaves, flower, and fruit glands. The essential oil of Cistus ladaniferus is extremely complex. In some cases, up to 300 compounds have been detected by GC (gas chromatography), most of them being only present as traces [9]. The GC chromatogram of the oil from C. ladaniferus var. maculatus from Morocco showed more than 50 components among which 30 were identified. The main components were the monoterpenoids (bornyl acetate (5.5 %) and pinocarveol (7.7 %)), and sesquiterpenoid alcohols (viridiflorol (7.2 %) and ledol (3.5 %)) [10]. Moreover, this plant is rich in flavonoids and phenolic compounds [4]. Lipid peroxidation (LPO) is a major cause of food deterioration, affecting colour, flavour, texture and nutritional value [11]. Antioxidants are of interest to the food industry, because they prevent rancidity [11, 12]. At the present time, the most commonly used antioxidants are butylated hydroxyanisole (BHA), butylated hydroxytoluene (BHT), propylgallate and tert-butyl hydroquinone. However, concern over the safety of synthetic antioxidants has increased consumers’ interest in natural antioxidants. Therefore, there has been great interest in finding natural M. Amensour :N. Skali-Senhaji : J. Abrini Laboratory of Biology and Health, Team Biotechnology and applied Microbiology, Department of Biology, Faculty of Science, Abdelmalek Essaadi University, BP 2121, 93002 Tetouan, Morocco

Antibacterial Activity of Extracts of Myrtus communis Against Food-Borne Pathogenic and Spoilage Bacteria

The following study was conducted to investigate the efficacy of several leaf and berry extracts against a range of food-borne pathogens and food spoilage bacteria. The methanol, ethanol, and ethyl acetate extracts of Myrtus communis leaves and berries were examined for in vitro antibacterial activity. The methanolic leaf extract of M. communis, which was seen to have antibacterial activity against Listeria monocytogenes CECT 4032 and Pseudomonas aeruginosa IH, was further investigated to determine the effect of the extract on viable counts of bacteria using the bacterial cell-death time. Most of the extracts showed relatively high antibacterial activity against most of the tested microorganisms. None of the extracts was active against Escherichia coli K12. The results obtained confirm the antibacterial potential of the extracts of M. communis.

Antimicrobial activities of the bacteriocin-like substances produced by lactic acid bacteria isolated from Moroccan dromedary milk

A total of 450 different colonies, isolated from 25 samples of dromedary milk collected from Laâyoune region of Morocco, were tested for antimicrobial compounds production. Out of these, 30 were determined to be lactic acid bacteria (LAB) and able to inhibit the growth of the indicator strain Listeria innocua CECT 4030. Seven isolates were selected by the large and clear zones of inhibition when tested by the agar well diffusion assay. They were classified by phenotypic and biochemical analysis as two Enterococcus durans (E204 and E214), two Lactococcus lactis (R75 and R76), one Enterococcus faecium R111, one Lactococcus cremoris R112 and one Enterococcus avium R122. Their antimicrobial compounds were detected in cell-free culture supernatant fluids under conditions that eliminate acid and hydrogen peroxide inhibition. The antimicrobial activity was altered after treatment with trypsin, -chymotrypsin, pepsin or papain which confirms the proteinaceous nature of the inhibition. It was heat stable even at autoclaving temperature (121°C for 15 min) and also active over a wide pH range (2 to 10). This fact suggests that bacteriocin-like produced by the seven LAB strains may find application as biopreservatives in food products. Key words: Dromedary milk, lactic acid bacteria, bacteriocin-like substances, antimicrobial activity.

Antioxidant activity and total phenolic compounds of myrtle extracts

The total phenolic content, flavonoid content and antioxidant activity of methanol, ethanol, water and ethyl acetate extracts of the leaves and berries of myrtle (Myrtus communis) were measured. Total phenolic content was assessed by the Folin-Ciocalteau assay, total flavonoid content was assessed by a colorimetric method using rutin as standard flavonoid, whereas antioxidant activity was assessed by measuring the ability of the extracts to scavenge the 2,2′-azinobis (3-ethylbenzothiazoline-6- sulphonic acid) diammonium salt (ABTS+) radical. The results pointed to the significant antioxidant activities of the methanol and water extracts, the overall strength being in the order of methanol > water > ethanol > ethyl acetate in both, leaf and berry extracts. In all cases, the extracts obtained from leaves showed higher antioxidant activity and higher total phenolic and flavonoid contents than the corresponding extracts obtained from berries. The phenolic content exhibited a strong association (r 2 = 0.9452) with antioxidant activity.

Determination of Phenol Content and Antibacterial Activity of FiveMedicinal Plants Ethanolic Extracts from North-West of Morocco

The aim of this study is to screening the phytochemical content of five medicinal plants of Ouezzane province for their antibacterial activity. Ethanolic extracts were prepared using solid-liquid extraction. The total phenolic content was assessed by the Folin-Ciocalteau assay, total flavonoid content was assessed by aliminuim chloride (AlCl3) colorimetric assay. The antibacterial activity of extracts was tested against two reference strains, Escherichia coli K12 MBLA and Staphylococus aureus CECT 976 using the agar well diffusion method. The total phenol content of five ethanolic extracts ranged between 34,64 ± 1,16 and 112,48 ± 1,75 mg GAE per g extract, and the flavonoid content ranged between 9,28 ± 1,37 and 24,55 ± 0,58 mg QE/g extract. In the determination of the in vitro antimicrobial activity, flowering extracts prevented the growth of the tested strain by forming significant inhibition zones. The inhibitory activity of Ajuva Iva ethanolic extracts was especially remarkable (17,5 mm against E. coli and 21 mm against S. aureus). These species could be considered as potential sources of antibacterial compounds. Further studies are necessary for chemical characterization of the active principles and more extensive biological evaluations.

Identification of Flavonoid Content and Chemical Composition of the Essential Oils of Moroccan Herbs: Myrtle (Myrtus communis L.), Rockrose (Cistus ladanifer L.) and Montpellier cistus (Cistus monspeliensis L.)

Abstract The aim of this work was to determine the polyphenol content and chemical composition of the essential oils of some Moroccan herbs: myrtle (Myrtus communis L.), rockrose (Cistus ladanifer L.) and montpellier cistus (Cistus monspeliensis L.). The polyphenols were analyzed and identified by HPLC and the essential oils were chemically analyzed and identified by GC/MS. The principal components of myrtle leaves essential oil were 1,8-cineole (40.37%) and α-pinene (21.82%). Major oil components of myrtle berry essential oil included 1,8-cineole (46.48%) and α-pinene (24.52%). The essential oil of rockrose was characterized by a high content of 1,8-cineole (19.27%) and viridiflorol (16.38%), while the predominant compounds in montpellier cistus essential oil were 1,8-cineole (9.17%), bornyl acetate (9.14%) and α-pinene (5.84%). Myrtle berry contains small amounts of myricetin derivates (myricetin-3-O-galactoside and myricetin-3-O-rhamnoside), although anthocyanins (malvidin-3-O-glucoside, petunidin-3-O-glucoside) are present in large amounts. In Cistus ladanifer and Cistus monspeliensis the predominant flavonoids were 3,7′-di-O-methyl-kaempferol and 3-O-methyl-kaempferol.

Determination of Phenolic Contents, Antioxidant and Antibacterial Activities of Strawberry Tree (Arbutus unedo L.) Leaf Extracts

Aims: This study was designed to evaluate the antibacterial and antioxidant activities of methanolic, ethanolic, ethyl acetate and n-hexanic extract from the leaves of Strawberry tree (Arbutus unedo L.) growing in Morocco. Study Design: Determination of total phenol and flavonoids content, in vitro antioxidant activity and antibacterial study of extracts. Place and Duration of Study: Department of Biology (Faculty of Sciences), between July 2015 and November 2015. Original Research Article Bouyahya et al.; BBJ, 14(3): 1-10, 2016; Article no.BBJ.26488 2 Methodology: The extracts were prepared using solid-liquid extraction. The total phenolic content was assessed by the Folin-Ciocalteau assay, total flavonoid content was assessed by aluminium chloride (AlCl3) colorimetric assay. The antibacterial activity of extracts was tested against five reference strains, Escherichia coli K12 MBLA, Staphylococus aureus CECT 976, Listeria monocytogenes serovar 4b CECT 4032 and Pseudomonas aeruginosa IH using the agar well diffusion method and the micro-dilution assays. The antioxidant activity was assessed by measuring the ability of the extracts to scavenge the 2,2-diphenyl-1picrylhydrazyl (DPPH). Results: The total phenol content of strawberry tree five extracts ranged between 94.51±0.08 and 141.72±0.56 mg GAE/g extract, and the flavonoid content ranged between 17.48±1.02 and 31.61±0.59 mg QE/g extract. All of the extracts presented antioxidant capacity assessed by DPPH scavenging method, but at different levels depending on the concentration and the extraction solvent are found. In addition, all extracts exhibited an antibacterial activity at different levels against strains reported as the causal agents of food borne diseases. Conclusion: Results suggest the potential use of tested A. unedo extracts as bio-preservatives in the functional food industry.

Growth of Enterococcus durans E204 producing bacteriocin-like substance in MRS Broth: Description of the growth and quantification of the bacteriocin-like substance

Bacteriocin-like substance E204 is an antimicrobial compound produced by Enterococcus durans E204 isolated from camel milk of Morocco that shows a broad spectrum of inhibitory activity against taxonomically related microorganisms. It is sensitive to digestive proteases. In the first study, de Man, Regosa and Sharpe (MRS) broth was inoculated by E204 strain, incubated for 30°C at 200 rpm and monitored by checking dry cell weight, nutrients consumption, lactic acid and bacteriocin-like productions. The maximum biomass (2.3 g/l) and antimicrobial activity (32 AUml -1 ) were obtained at 12 h of incubation. No increase in the production of bacteriocin-like was recorded after the exponential phase. In the other hand, the quantification of the antimicrobial activity was carried out by a photometric assay on culture tubes based on the determination of the ID50 dose causing 50% growth inhibition of Enterococcus faecium 410 CECT in 6 h of incubation. The highest bacteriocin-like titre (279.71 BUml -1 ) was obtained at acidic pH (3.5) and at 70°C after 10 min of incubation. Key words : Enterococcus durans, bacteriocin-like, MRS broth, nutrients consumption, quantification.

Combinations of nisin with salt (NaCl) to control Listeria monocytogenes on sheep natural sausage casings stored at 6°C

This study evaluated the effect of combinations of nisin with salt (NaCl) to control Listeria monocytogenes on sheep natural sausage casings. Casings were inoculated with 3.0 x 105 cfu/g final inocula of L. monocytogenes, stored at 6°C in different solutions of nisin at 0, 100, 150 and 200 ig/g. Each combined with salt at 0, 4, 7 and 12% (w/v). Samples were taken at day 0, 10, 20, 35, 60 and 90 post-inoculation and the number of bacteria present was determined. The bactericidal effect of nisin against L. monocytogenes cells was evident where nisin was applied in combination with salts. In all treatments, nisin/salt mixtures induced a bacterial growth inhibitory effect greater than salt alone. These results indicate that nisin and salt synergistically and significantly inhibit the growth of L. monoctogenes in sheep natural casings. The use of nisin combined with salt as antibacterial agent will be appropriate for applications on natural sausage casing industries as natural preservatives to control foodborne pathogens. They can be used as growth inhibitors of L. monocytogenes, an important foodborne pathogens and spoiling bacterium. The main reason for their appropriateness is their natural origin, which consumers find comforting. These beneficial characteristics could increase casings safety and shelf life.